<h3>描述</h3>
<p>referElem：定位参考元素，接口传值表示drop不添加在body上，而是跟随宿主</p>
<h3>示例</h3>

<span>改变位置：</span><button style="margin-right: 10px" *ngFor="let item of positions" (click)="change(item)">{{item}}</button>
<h4>1.跟随宿主元素</h4>
<br /><br /><br /><br />
<span>
  <span style="display: inline-block; margin-left: 200px" #refer>
    <input #dominator style="width: 120px" (click)="drop.toggle()" (blur)="drop.hide()" />
  </span>
  <ti-drop #drop [referElem]="refer" [dominatorElem]="dominator" [determinPositionFn]="positionFn" panelWidth="150px">
    <div style="width: 100%; height: 100px; background-color: chocolate"></div>
  </ti-drop>
</span>

<h4>2.宿主元素的祖先元素有fixed定位</h4>
<br /><br /><br /><br />
<div style="position: fixed">
  <span style="display: inline-block; margin-left: 200px" #refer2>
    <input #dominator2 style="width: 120px" (click)="drop2.toggle()" (blur)="drop2.hide()" />
  </span>
  <ti-drop #drop2 [referElem]="refer2" [dominatorElem]="dominator2" [determinPositionFn]="positionFn" panelWidth="150px">
    <div style="width: 100%; height: 100px; background-color: chocolate"></div>
  </ti-drop>
</div>
<br />
